American Crystal Sugar Co. officials say the company's chief executive officer will not be attending a proposed meeting with locked-out union workers.

The union has invited Crystal Sugar CEO Dave Berg to an Aug. 16 gathering that union negotiator Steven Bertelli on Wednesday described as an "informative, constructive discussion that could contribute to productive negotiations."

In a letter posted on the Crystal website, a lawyer for the company says the issues have been outlined in 21 negotiating sessions and a public meeting will not resolve the dispute.

About 1,300 workers have been locked out of their jobs for more than a year at facilities in Minnesota, North Dakota and Iowa.

The union says the contract offer is unfair, particularly on seniority and job security, and voted against it three times.